Layer order in map themes must always respect project layer order

python/core/qgsmapthemecollection.sip

@@ -102,62 +102,22 @@ class QgsMapThemeCollection : QObject
     //! Returns a list of existing map theme names.
     QStringList mapThemes() const;
 
-    /**
-     * Returns the recorded state of a map theme.
-     */
-    MapThemeRecord mapThemeState( const QString& name ) const;
 
-    /**
-     * Returns the list of layer IDs that are visible for the specified map theme.
-     *
-     * @note The order of the returned list is not guaranteed to reflect the order of layers
-     * in the canvas.
-     * @note Added in QGIS 3.0
-     */
-    QStringList mapThemeVisibleLayerIds( const QString& name ) const;
 
-    /**
-     * Returns the list of layers that are visible for the specified map theme.
-     *
-     * @note The order of the returned list is not guaranteed to reflect the order of layers
-     * in the canvas.
-     * @note Added in QGIS 3.0
-     */
-    QList<QgsMapLayer*> mapThemeVisibleLayers( const QString& name ) const;
 
-    /**
-     * Get layer style overrides (for QgsMapSettings) of the visible layers for given map theme.
-     */
-    QMap<QString, QString> mapThemeStyleOverrides( const QString& name );
 
-    /**
+    MapThemeRecord mapThemeState( const QString &name ) const;
-     * Reads the map theme collection state from XML
+    QStringList mapThemeVisibleLayerIds( const QString &name ) const;
-     * @param doc DOM document
+    QList<QgsMapLayer *> mapThemeVisibleLayers( const QString &name ) const;
-     * @see writeXml
+    QMap<QString, QString> mapThemeStyleOverrides( const QString &name );
-     */
+    void readXml( const QDomDocument &doc );
-    void readXml( const QDomDocument& doc );
+    void writeXml( QDomDocument &doc );
+    static MapThemeRecord createThemeFromCurrentState( QgsLayerTreeGroup *root, QgsLayerTreeModel *model );
+    void applyTheme( const QString &name, QgsLayerTreeGroup *root, QgsLayerTreeModel *model );
+    QgsProject *project();
+    void setProject( QgsProject *project );
+    QList< QgsMapLayer * > masterLayerOrder() const;
 
-    /** Writes the map theme collection state to XML.
-     * @param doc DOM document
-     * @see readXml
-     */
-    void writeXml( QDomDocument& doc );
-
-    /**
-     * Static method to create theme from the current state of layer visibilities in layer tree,
-     * current style of layers and check state of legend items (from a layer tree model).
-     * @note added in QGIS 3.0
-     */
-    static MapThemeRecord createThemeFromCurrentState( QgsLayerTreeGroup* root, QgsLayerTreeModel* model );
-
-    /**
-     * Apply theme given by its name and modify layer tree, current style of layers and checked
-     * legend items of passed layer tree model.
-     * @note added in QGIS 3.0
-     */
-    void applyTheme( const QString& name, QgsLayerTreeGroup* root, QgsLayerTreeModel* model );
-    QgsProject* project();
-    void setProject( QgsProject* project );
   signals:
 
     void mapThemesChanged();

src/core/qgsmapthemecollection.cpp

@@ -175,6 +175,14 @@ void QgsMapThemeCollection::setProject( QgsProject *project )
   emit projectChanged();
 }
 
+QList<QgsMapLayer *> QgsMapThemeCollection::masterLayerOrder() const
+{
+  if ( !mProject )
+    return QList< QgsMapLayer * >();
+
+  return mProject->layerOrder();
+}
+
 
 bool QgsMapThemeCollection::hasMapTheme( const QString &name ) const
 {
@@ -229,23 +237,26 @@ QStringList QgsMapThemeCollection::mapThemes() const
 QStringList QgsMapThemeCollection::mapThemeVisibleLayerIds( const QString &name ) const
 {
   QStringList layerIds;
-  Q_FOREACH ( const MapThemeLayerRecord &layerRec, mMapThemes.value( name ).mLayerRecords )
+  Q_FOREACH ( QgsMapLayer *layer, mapThemeVisibleLayers( name ) )
   {
-    if ( layerRec.layer() )
+    layerIds << layer->id();
-      layerIds << layerRec.layer()->id();
   }
   return layerIds;
 }
 
-
 QList<QgsMapLayer *> QgsMapThemeCollection::mapThemeVisibleLayers( const QString &name ) const
 {
   QList<QgsMapLayer *> layers;
-  Q_FOREACH ( const MapThemeLayerRecord &layerRec, mMapThemes.value( name ).mLayerRecords )
+  const QList<MapThemeLayerRecord> &recs = mMapThemes.value( name ).mLayerRecords;
+  Q_FOREACH ( QgsMapLayer *layer, masterLayerOrder() )
   {
-    if ( layerRec.layer() )
+    Q_FOREACH ( const MapThemeLayerRecord &layerRec, recs )
-      layers << layerRec.layer();
+    {
+      if ( layerRec.layer() == layer )
+        layers << layerRec.layer();
+    }
   }
+
   return layers;
 }
 

src/core/qgsmapthemecollection.h

@@ -242,6 +242,13 @@ class CORE_EXPORT QgsMapThemeCollection : public QObject
      */
     void setProject( QgsProject *project );
 
+    /**
+     * Returns the master layer order (this will always match the project's QgsProject::layerOrder() ).
+     * All map themes will maintain the same layer order as the master layer order.
+     * @note added in QGIS 3.0
+     */
+    QList< QgsMapLayer * > masterLayerOrder() const;
+
   signals:
 
     /**

tests/src/python/test_qgsmapthemecollection.py

@@ -97,6 +97,58 @@ class TestQgsMapThemeCollection(unittest.TestCase):
         app.processEvents()
         self.assertEqual(len(theme_changed_spy), 6) # signal should be emitted - layer is in record
 
+    def testMasterLayerOrder(self):
+        """ test master layer order"""
+        prj = QgsProject()
+        layer = QgsVectorLayer("Point?field=fldtxt:string",
+                               "layer1", "memory")
+        layer2 = QgsVectorLayer("Point?field=fldtxt:string",
+                                "layer2", "memory")
+        layer3 = QgsVectorLayer("Point?field=fldtxt:string",
+                                "layer3", "memory")
+        prj.addMapLayers([layer, layer2, layer3])
+
+        prj.setLayerOrder([layer2, layer])
+        self.assertEqual(prj.mapThemeCollection().masterLayerOrder(), [layer2, layer])
+
+        prj.setLayerOrder([layer, layer2, layer3])
+        # make some themes...
+        theme1 = QgsMapThemeCollection.MapThemeRecord()
+        theme1.setLayerRecords([QgsMapThemeCollection.MapThemeLayerRecord(layer3),
+                                QgsMapThemeCollection.MapThemeLayerRecord(layer)])
+
+        theme2 = QgsMapThemeCollection.MapThemeRecord()
+        theme2.setLayerRecords([QgsMapThemeCollection.MapThemeLayerRecord(layer3),
+                                QgsMapThemeCollection.MapThemeLayerRecord(layer2),
+                                QgsMapThemeCollection.MapThemeLayerRecord(layer)])
+
+        theme3 = QgsMapThemeCollection.MapThemeRecord()
+        theme3.setLayerRecords([QgsMapThemeCollection.MapThemeLayerRecord(layer2),
+                                QgsMapThemeCollection.MapThemeLayerRecord(layer)])
+
+        prj.mapThemeCollection().insert('theme1', theme1)
+        prj.mapThemeCollection().insert('theme2', theme2)
+        prj.mapThemeCollection().insert('theme3', theme3)
+
+        #order of layers in theme should respect master order
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayers('theme1'), [layer, layer3])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayers('theme2'), [layer, layer2, layer3])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayers('theme3'), [layer, layer2])
+
+        # also check ids!
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayerIds('theme1'), [layer.id(), layer3.id()])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayerIds('theme2'), [layer.id(), layer2.id(), layer3.id()])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayerIds('theme3'), [layer.id(), layer2.id()])
+
+        # reset master order
+        prj.setLayerOrder([layer2, layer3, layer])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayers('theme1'), [layer3, layer])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayers('theme2'), [layer2, layer3, layer])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayers('theme3'), [layer2, layer])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayerIds('theme1'), [layer3.id(), layer.id()])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayerIds('theme2'), [layer2.id(), layer3.id(), layer.id()])
+        self.assertEqual(prj.mapThemeCollection().mapThemeVisibleLayerIds('theme3'), [layer2.id(), layer.id()])
+
 
 if __name__ == '__main__':
     unittest.main()